The homopolymer of 7,oxa-bicyclo(2,2,1)heptane and of its alkyl-derivatives is known and described in the technical literature. This homopolyer shows a crystallinity at x-rays and is poorly soluble in most common solvents, and has the drawback that its melting temperature, which is generally higher than 350.degree. C., is higher than its decomposition temperature. This set of properties make the homopolymer not very interesting from an industrial viewpoint, due to fabricating difficulties.